Battery cable clamp



Dec. 3, 1957 A. J BOONE BATTERY CABLE CLAMP F l d F b 7 1955 mmvron. ALBERT J Boo/v5 BY W E fi BATTERY CABLE CLAMP Albert J. Boone, Cleveland, Ohio Application February 7, 1955, Serial No. 486,359

3 Claims. (Cl. 339-237) condition, or at least destroy electrical conductivity to the extent that large amperages cannot be carried for; 30

starter loads.

Therefore, an object of this invention is to provide a cable terminal having a shaped portion to closely fit the surface of a battery terminal and provide a separate clamp device to hold the skirt portion in good contact.

Another object of this invention is to provide a terminal device of separable parts particularly adapted to prevent disengagement by vibration, and to provide for disengagement of the parts when encrusted with corrosion with no danger of damage to the terminal post.

Still another object of this invention is to provide formaximum ease of installation and removal with conven' tional tools.

And yet another object of this invention is to provide for maximum flexibility in cable positioning with respect to a battery surface.

Other objects and a fuller understanding of this invention may be had by referring to the following specification and claims, taken in conjunction with the accompanying drawing, in which:

Figure 1 is a cross sectional view of the preferred embodiment of the connecting device;

Figure 2 is a top view of the connecting devicegand,

Figure 3 is a sectional view taken along the line 3-3 of Figure 2.

Although the principles of the present invention may well be applied to attachment to other types of terminal posts, the drawing and the balance of this specification will be directed to the attachment of a cable to the terminal post of a conventional automotive type storage battery. In the drawing a portion of a battery is illustrated as having a tapered lead battery post 11 extending from the top surface thereof. A cable 12 is attached to the post 11 by means of a terminal device embodying the principles of this invention. A cable terminal 13 is suitably attached to the cable 12. In the illustrated embodiment of the cable terminal 13 there is provided an attachment portion 14 and a skirt portion 15. The cable terminal 13 may be made quite readily by conventional stamping methods. if desired. in the drawing a boss 17 carrying a bolt 18 threadably engaged therein is provided to mechanically engage the terminals present Z,815, ifiii Patented Dec. 3, 1957 ICC cable 12 into the attachment portion 14, although mechanical engagement is not a requisite. Solder sweating is generally employed regardless of whether or not the mechanical attachment is employed.

The skirt portion is formed to partially circumscribe the surface of the battery post 11, and therefore has a cross sectional configuration of generally C-shape. "the size of the C-shaped cross sectional configuration increases progressively from the top near the attachment portion 14 .to the bottom of the skirt.

Because of the C-form of the cross section of skirt 15, the skirt ends in forward edges 16. A decided improvement in electrical and mechanical interconnection of the cable terminal 13 has been found to accrue by making the C-shape cross sectional configuration with the distance across the edges 16 slightly undersized or even turned inwardly. Thus by forcing the skirt 15 into engagement with the post 11, the edges 16 are caused to gouge through the normally oxidized dirty and rough surface found on battery terminals such as the terminal post 11. This action effects a contact with clean, fresh metal and provides a measure of mechanical interconnection.

Prior devices have provided for somewhat cupped plates to contact battery terminals but such forms should not be confused with the present invention which pro vides a new and very unique function. One of the principle 'difficulties with prior art battery connecting devicesiis the problem of avoiding disengagement of the cableterminal by vibration and yet providing means for easily. breaking the encrustration of corrosion formations Without danger of damaging the relatively soft battery terminal post or its supporting structure. According to this invention a clamp 20 completely separate and independent from the cable terminal 13 is adapted to press the skirt 15 into engagement with the post 11. The construction and operation of the clamp 20 provides holding forces opposing the normal vibration tendencies. Because of the separate nature of the cable terminal 13 and the clamp 20, corrodable surfaces are divided and corrosion breaking forces may be applied most advantageously. The clamp 20, in the illustrated embodiment, is essentially an annular wall 21 which defines an oblong and tapered opening 22 therethrough. Being an oblong opening, a major and a minor axis are provided. Reference to Figures 2 and 3 will at once illustrate the fact that the distance across the edges 16 of the skirt 15 at the bottom end thereof is considerably greater than the minor axis at the top of the opening 22 but less than the major axis at the top. Thus the skirt 15 must be inserted into the opening 22 with the maximum distance across the edges 16 extending along the major axis of the opening whereupon it may thereafter be turned to a locking position as illustrated in Figure 2. Such turning possibility is provided because of the tapered nature of the opening 22. At the bottom of the opening 22 the minor axis is sutficiently large to accommodate the distance across the edges 16, as illustrated best in Figure 3. In other words, the taper of the opening 22 is provided to correspond closely with the flair of the skirt 15.

From the illustration in Figure 2 and foregoing description, it will be appreciated that the interlocking shape of the flaired skirt 15 and the tapered opening 22 will prevent vertical disengagement of the cable terminal 13 from the clamp 20. Such formation together with the aid provided by gouging of the edges 16 into the material of the post 11 prevents disengagement by vibration.

As a further aid to the prevention of unintentional disengagement by vibration, a clamping bolt 24 is threadably engaged through a threaded opening 23 in the clamp 20. Bolt 24 extends in the direction of the major axis of opening 22, and therefore will press against the skirt 15 and will force the skirt against the surface of the post 11. However, the threaded opening 23 extends in a downwardly direction with respect to the longitudinal axis of the opening 22. The slope of the opening 23 is intended to correspond to the taper of the post 11. Battery terminal posts are normally provided at a 3 angle. Accordingly, the slope of the opening 23 will normally be at 3. Thus the bolt 24 will extend in adirection normal to the surface of the post 11 for the purpose of applying the best holding pressure on the skirt 15. A greater degree of taper may be provided if desired, but a slope closely corresponding to the taper of the post is recommended.

The separate two-piece construction of the present invention provides for easy disengagement after corrosion has taken place. To produce such separation the bolt 24 is backed away from the skirit 15. The tapered positioning of the bolt 24 provides an unexpected and desirable function for aiding in such backing off of the bolt. By such sloping provision the head of the bolt 24 is positioned a maximum distance away from the surface of the battery 10. Thus a conventional wrench may-be quite easily placed upon the head of the belt. I minal construction the heads of such clamping bolts are usually placed such that an open end wrench is the only gyrie of wrench that can be engaged with the clamping After the bolt 24 has been backed away from the skirt 15, a tapping blow on the head of the bolt 24 will place the corroded surfaces under a severe tensile shock strain. Since most materials, and particularly corrosive products, are weak in tensil, such tensil shock blow will break any corroded interconnection between the inner surface of the opening 22 and the contacting surface of the battery post 11. Thus the clamp is quite readily broken free from the battery post 11 in spite of heavy corrosion. It should be noted that the two-piece separate construction reduces the amount of surface contact between the clamp 20 and the post 11, and therefore aids in such easy separation. Likewise, the two-piece construction reduces the amount of contact surface between the skirt 15 and the post 11. After the clamp 20 has been broken loose the skirt 15 may be readily broken by a rotary or tipping force produced by lifting on the attachment portion 14, such as by pulling upwardly on the cable 12. It has been found that the skirt portion 15 will thus again produce tensil forces most conducive to separation of corroded surfaces and the most heavily corroded surfaces have been found to break free quite readily.

In summary, therefore, the advantages obtained by the present invention are that the edges of the skirt 15 dig mto a battery post 11 to provide the best electrical and mechanical contact possible. The clamping screw of the clamp device is at an angle to position the head of the clamping screw or bolt off of the battery surface and also to allow the clamp to be positioned in any direction around the battery surface. Prior art devices with such bolts are limited to relatively few positions because of clearance problems. of battery terminals without the use of shims for undersize posts. One wrench is all that is required for installing or disconnecting the terminal device, and the wrench may be a closed box wrench or a socket instead of an open end Wrench. And finally, an outstanding advantage is the ease of breaking corroded surfaces as described because of the independent and separate two-piece construction.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted towithout departing from the spirit and the scope of the invention as hereinafter claimed.

In conventional ter-- This terminal device fits all sizes I claim:

1. A terminal connecting device for connecting a cable to a tapered battery post, comprising, a cable and terminal having a cable attachment portion and a skirt portion, said skirt portion having a tapered form of generally C-shape in cross sectional configuration to circumscribe a portion of the battery terminal, the tapered form thereby providing a greatest dimension across the skirt portion at the end thereof, a separate clamp means having an annular wall defining a central opening of elongated form having a major and a minor axis, said opening having a top and a bottom entrance, at said top entrance said major axis being greater than the greatest dimension of said skirt portion, said minor axis being greater than the smallest dimension of the skirt portion and smaller than the said greatest dimension, and screw means threadably carried by said clamp, said screw means extending into said central opening in the direction of said major axis to exert a clamping force against said skirt portion and terminal post.

2. A terminal connecting device for connecting a cable to a tapered battery post, comprising, a cable end terminal having a cable attachment portion and a skirt portion, said 'skirt portion having a tapered form of generally C-shape in cross sectional configuration to circumscribe a portion of the battery terminal, the tapered form thereby providing a greatest dimension across the skirt portion at the end thereof, a separate clamp means having an annular wall I defining a central opening of elongated form having a dimension of the skirt portion and smaller than the said greatest dimension, said opening being tapered from the top entrance to the bottom entrance, at said bottom entrance the minor axis being as great as the said greatest dimension of the skirt portion, and screw means threadably carried by said clamp, said screw means extending into said central opening in the direction of said major axis to exert a clamping force against said skirt portion and terminal post.

3. In combination, a battery post and a terminal con- I necting device attached thereto, said terminal connecting device comprising a cable end terminal and a clamp securing the cable end terminal to the post, said post being frusto conical in form, said terminal having a cable attachment portion and a skirt portion, said skirt portion circumscribing a portion of the terminal post, said clamp having an annular wall defining a central opening, said post and said skirt portion residing within said central opening with the skirt portion positioned upon the surface of the terminal post, said skirt portion having a concave inner surface shaped substantially to the form of the said battery post and ending in first and second lateral wall edges, at least a portion of said first and second wall edges being spaced a distance less than the corresponding dimension of the battery post, and screw means threadably carried by said clamp contacting the skirt portion and exerting a clamping force driving said first and second wall edgeswith a gouging action into the body of the battery terminal for good electrical contact and mechanical interconnection to resist loosening by vibration.

References Cited in the file of this patent UNITED STATES PATENTS 

